Some CDC_NCM devices are used as docks for laptops. In this case, it
makes sense to accept multicast Ethernet traffic, as these devices
can reside in a proper LAN. Without this, mDNS or IPv6 simply do not
work.
Signed-off-by: Miguel Rodríguez Pérez <miguel@xxxxxxxxxxxxx>
---
drivers/net/usb/cdc_ncm.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index d6b51e2b9495..50af1d9d0102 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -132,6 +132,33 @@ static void cdc_ncm_get_strings(struct net_device
__always_unused *netdev, u32 s
static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32
new_tx);
+static void cdc_ncm_update_filter(struct usbnet *dev)
+{
+ struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
+ u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
+ struct net_device *net = dev->net;
+
+ u16 cdc_filter = USB_CDC_PACKET_TYPE_DIRECTED
+ | USB_CDC_PACKET_TYPE_BROADCAST;
+
+ /* filtering on the device is an optional feature and not worth
+ * the hassle so we just roughly care about snooping and if any
+ * multicast is requested, we take every multicast
+ */
+ if (net->flags & IFF_PROMISC)
+ cdc_filter |= USB_CDC_PACKET_TYPE_PROMISCUOUS;
+ if (!netdev_mc_empty(net) || (net->flags & IFF_ALLMULTI))
+ cdc_filter |= USB_CDC_PACKET_TYPE_ALL_MULTICAST;
+
+ usbnet_write_cmd(dev,
+ USB_CDC_SET_ETHERNET_PACKET_FILTER,
+ USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
+ cdc_filter,
+ iface_no,
+ NULL,
+ 0);
+}
+
static const struct ethtool_ops cdc_ncm_ethtool_ops = {
.get_link = usbnet_get_link,
.nway_reset = usbnet_nway_reset,
@@ -1652,6 +1679,7 @@ static const struct driver_info cdc_ncm_info = {
.status = cdc_ncm_status,
.rx_fixup = cdc_ncm_rx_fixup,
.tx_fixup = cdc_ncm_tx_fixup,
+ .set_rx_mode = cdc_ncm_update_filter,
};
/* Same as cdc_ncm_info, but with FLAG_WWAN */
--
2.17.1
On 30/06/18 13:21, Miguel Rodríguez Pérez wrote:
> Sending again, as the previous try had the wrong subjects. Sorry about that.
>
> Dell D6000 dock (and I guess other docks too) exposes a CDC_NCM device
> for Ethernet traffic. However, multicast Ethernet traffic is not
> processed making IPv6 not functional. Other services, like mDNS used for
> LAN service discovery are also hindered.
>
> The actual reason is that CDC_NCM driver was not processing requests to
> filter (admit) multicast traffic. I provide two patches to the linux
> kernel that admit all Ethernet multicast traffic whenever a multicast
> group is being joined.
>
> The solution is not optimal, as it makes the system receive more traffic
> than that strictly needed, but otherwise this only happens when the
> computer is connected to a dock and thus is running on AC power. I
> believe it is not worth the hassle to join only the requested groups.
> This is the same that is done in the CDN_ETHER driver.
>
> Best regards,
>
--
Miguel Rodríguez Pérez
Laboratorio de Redes
EE Telecomunicación – Universidade de Vigo
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
